Re: [PATCH] i2c: Prevent runtime suspend of adapter when Host Notify is required

From: Greg KH <greg@kroah.com>
To: Charles Keepax <ckeepax@opensource.cirrus.com>
Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-i2c@vger.kernel.org, Wolfram Sang <wsa@the-dreams.de>,
	stable@vger.kernel.org
Subject: Re: [PATCH] i2c: Prevent runtime suspend of adapter when Host Notify is required
Date: Sun, 5 May 2019 14:54:40 +0200	[thread overview]
Message-ID: <20190505125440.GA25640@kroah.com> (raw)
In-Reply-To: <20190502153251.GG81578@ediswmail.ad.cirrus.com>

On Thu, May 02, 2019 at 04:32:51PM +0100, Charles Keepax wrote:
> On Thu, May 02, 2019 at 03:32:24PM +0300, Jarkko Nikula wrote:
> > On 4/30/19 6:56 PM, Sasha Levin wrote:
> > >This commit has been processed because it contains a "Fixes:" tag,
> > >fixing commit: c5eb1190074c PCI / PM: Allow runtime PM without callback functions.
> > >
> > >The bot has tested the following trees: v5.0.10, v4.19.37.
> > >
> > >v5.0.10: Build OK!
> > >v4.19.37: Failed to apply! Possible dependencies:
> > >     6f108dd70d30 ("i2c: Clear client->irq in i2c_device_remove")
> > >     93b6604c5a66 ("i2c: Allow recovery of the initial IRQ by an I2C client device.")
> > >
> > >
> > >How should we proceed with this patch?
> > >
> > There's also dependency to commit
> > b9bb3fdf4e87 ("i2c: Remove unnecessary call to irq_find_mapping")
> > 
> > Without it 93b6604c5a66 doesn't apply.
> > 
> > Otherwise my patch don't have dependency into these so I can have
> > another version for 4.19 if needed.
> > 
> > I got impression from the mail thread for 6f108dd70d30 that it could
> > be also stable material but cannot really judge.
> > 
> > Charles: does your commits b9bb3fdf4e87 and 6f108dd70d30 with the
> > fix 93b6604c5a66 qualify for 4.19? (background: my fix doesn't apply
> > without them but doesn't depend on them).
> > 
> 
> b9bb3fdf4e87 ("i2c: Remove unnecessary call to irq_find_mapping")
> 
> I don't think this one would make sense to backport it's not
> fixing any issues it just removes a redundant call. The call just
> repeats work it does no harm.
> 
> 6f108dd70d30 ("i2c: Clear client->irq in i2c_device_remove")
> 93b6604c5a66 ("i2c: Allow recovery of the initial IRQ by an I2C client device.")
> 
> These two are much more of a grey area, they do fix an actual
> issue, although that issue only happens when you unbind and
> rebind both an I2C device and the device providing its IRQs. A
> couple of us have been trying to look for a better fix as well
> which further complicates matters.
> 
> I would suggest you just backport your patch and leave these
> ones. As evidenced by the fixup patch there is a slight chance
> of regressions from backporting this fix and the issue it
> fixes is clearly not something people are normally hitting.

I've queued all of these up now, as they make sense to have for 4.19.y.

thanks,

greg k-h